Currently, a mobile terminal searches a cell network to find a cell that can be camped on and acquires a network service through camping. When the mobile terminal enters a network coverage area from a network coverage hole, the mobile terminal traverses all frequency bands allowed by a Public Land Mobile Network (PLMN) and selects a suitable cell to camp on. This process is referred to as cell selection.
The cell on which the mobile terminal camps is referred to as a serving cell. In the prior art, the mobile terminal periodically performs reselection detection. For example, the mobile terminal monitors, according to a cell reselection neighboring cell frequency band configuration table indicated by a Broadcast Control Channel (BCCH) system message of the serving cell, all neighboring cell levels and neighboring cell synchronization messages in the table that are received by a BCCH carrier, sorts the received neighboring cell levels in descending order, and extracts all types of system messages and control messages in each neighboring cell. When a comprehensive condition of a neighboring cell in the table is superior to that of the current serving cell, the mobile terminal reselects this neighboring cell as a new serving cell. This process is referred to as cell reselection. When a comprehensive condition of any neighboring cell is inferior to that of the current serving cell, the mobile terminal chooses to still camp on the serving cell, and does not reselect a neighboring cell.
Several problems occur during processes in which the mobile terminal performs cell selection and cell reselection. For example, when the mobile terminal selects a cell for the first time, if there is no suitable cell to camp on in all frequency bands allowed by the PLMN, the mobile terminal directly enters a no-service state. In addition, when the mobile terminal periodically performs cell reselection detection, if there is no suitable neighboring cell for the mobile terminal to camp on and the current serving cell does not meet a connection requirement due to worsened network coverage, the mobile terminal is dropped from the network.